Accidentally Accurate: Uderzo received a mail congratulating him for his perfect depiction of the antique roadstead of Brest. Uderzo had actually drawn it without doing any research.
The Catch Phrase Catches On: The expression "Il est tombé dedans quand il était petit." ("He fell into it [the magic potion] when he was little.") is now standard in French to designate something you got an interest to from a very young age.